this is tough but i had to go with a newer beat, but the first time i heard this was insane, the man to praise off of perseverance.
my second runner up is, ghetto rhyme story-remix- this shit gives me goosebumps to this day.
and my third is the woman behind me-remix. percee p fucking sounds incredible on these beats but yea all time favorite madlib beat- the man to praise

this is rough but hmm maybe not in any real order....
The Clown(episode c)
Come on Feet
Fire in the Hole
Survival Test
....... damn.. that fun to go through and see which ones you have had as your favorites along the way.. nice

YNQ - Many Thoughts (off the Ugly Betty EP)
Happy Home (off the Liberation album)
Raid (off Madvillainy)
The Unseen (The Unseen)
Green Power (The Unseen)
No Time For Jokes (off the Perseverance Madlib Remixes album)

Good pick. I guess I'd go with Snake Charmer. I first heard this shit as an interlude on the MED album and was blown away by it, II'll never forget it comes in at exactly 3:00 on Hold Your Breath. Then he brought out the full version on Movie Scenes Vol 2. Insane thumpery.